Flight from winter to summer and vice versa: consequences for the body of different age groups Introduction: the challenge of chronobiology and adaptation Quick changes in climate and time zones (jet lag) combined with extreme seasonal changes represent a powerful stress for all regulatory systems of the body. This is not just "acclimatization", but a comprehensive restructuring of circadian rhythms, thermoregulation, vegetative tone, and immune response. The consequences of such a transition differ fundamentally for children, adults, and the elderly due to the age-specific characteristics of physiology and adaptive reserve. Physiological basis of stress: more than just a change in temperature The body is faced with a triple blow: Disorientation of circadian rhythms. A failure in "internal clocks" located in the suprachiasmatic nucleus of the hypothalamus. The production of melatonin (sleep hormone), cortisol (stress and alertness hormone), and digestive enzymes is disrupted. The body continues to live in "winter" mode when it's "summer" outside, and vice versa. Extreme thermoregulatory shock. An emergency reprogramming of the heat exchange system is required: from working in conditions of cold stress with maximum heat preservation to a cooling mode through sweating and expansion of peripheral vessels, which creates a load on the cardiovascular system. Immunological provocation. A sharp change in the environment (new allergens, pathogens, temperature) temporarily reduces the effectiveness of the immune response, increasing the risk of respiratory and intestinal infections ("traveler's diarrhea"). Age groups: differentiated analysis of risks 1. Children (especially preschool and elementary school age) The child's body has high plasticity, but its regulatory systems are still immature. Consequences: The manifestations are bright and fast: sleep disturbances (the child confuses day and night), moodiness, disturbances in appetite and digestion, possible fever due to str ... Read more